revert: do not change the default

backend/apps/rag/search/searxng.py

@@ -37,7 +37,7 @@ def search_searxng(
     """
 
     # Default values for optional parameters are provided as empty strings or None when not specified.
-    language = kwargs.get("language", "auto")
+    language = kwargs.get("language", "en-US")
     safesearch = kwargs.get("safesearch", "1")
     time_range = kwargs.get("time_range", "")
     categories = "".join(kwargs.get("categories", []))